Memory Device Signal Lines with Open Stubs for Reflection Control
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Solution Overview
Problem
As electronic devices with increasing operating speeds and integration levels face challenges in maintaining signal reliability due to reflection signals caused by impedance mismatching between memory devices connected through the same channel, existing techniques struggle to effectively attenuate these signals, particularly at high-speed operations.
Innovation Solution
The electronic device incorporates a memory controller and multiple memory devices connected via signal lines with specific length ratios and stubs to reduce the influence of reflection signals, where the length of signal lines between branch points is adjusted to minimize signal distortion, and stubs are used to further attenuate reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If signal lines are extended to connect multiple memory devices through the same channel, then device integration and productivity are improved, but signal reflection and reliability deteriorate due to impedance mismatching
Solution Approach 1:
A stub (intermediary component) is introduced between the signal line and the memory device to act as a mediator. The stub provides an alternative path for signal reflection, preventing direct impedance mismatching between the signal line and the memory device, thereby reducing signal reflection while maintaining the extended signal line configuration for high integration.
Solution Approach 2:
The impedance parameter of the stub is specifically designed to match or complement the signal line impedance. By adjusting the stub's electrical parameters (length, width, position), the overall impedance characteristics of the signal path are optimized to minimize reflections, allowing extended signal lines to maintain signal integrity despite increased length.
2Productivity
If operating speed is increased to improve performance, then productivity is improved, but signal reflection becomes more severe worsening reliability
Solution Approach 1:
The stub serves as an intermediary that becomes increasingly effective at higher frequencies. By positioning the stub at specific locations along the signal line, it provides frequency-dependent impedance transformation that counteracts reflection effects that worsen with increasing operating speed, enabling high-speed operation while maintaining signal integrity.
3Reliability
If stubs are added to attenuate reflection signals, then signal reliability is improved, but device complexity increases
Solution Approach 1:
The signal line is segmented into multiple sections by introducing stubs at specific locations. Each stub creates a localized impedance transformation zone, dividing the overall signal path into manageable segments. This segmentation approach allows reflection control without requiring complete redesign of the entire signal distribution network, thereby limiting the increase in complexity.
Solution Approach 2:
Instead of uniformly modifying the entire signal line, stubs are strategically placed only at critical locations where impedance mismatching occurs. This local quality approach applies the complexity-reducing solution only where necessary, rather than throughout the entire signal distribution network, minimizing the overall increase in device complexity while maintaining signal reliability.
Data Source
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Figure 3A
AI summary
Disclosed is an electronic device which includes a plurality of memory devices, a memory controller, a first signal line that makes electrical connection between the memory controller and a first branch point, a second signal line that makes electrical connection between the first branch point and a second branch point, a third signal line that makes electrical connection between the first branch point and a third branch point, a fourth signal line that electrically connects the second branch point and the first memory device, a fifth signal line that electrically connects the second branch point and the second memory device, a sixth signal line that electrically connects the third branch point and the third memory device, and a stub that includes a first end electrically connected with at least one of the plurality of signal lines, and a second end being left open-circuit.